Apparatus for monitoring usage of a telephone

ABSTRACT

Apparatus for monitoring usage of a telephone connected across tip and ring terminals of a telephone system. The apparatus includes status circuitry operative under microprocessor control to repetitively sample the voltage across the tip and ring terminals and to examine the sampled voltages to determine whether the telephone is in an on/hook condition or an off/hook condition. When the telephone is in an off/hook condition an output of a first value is produced by the status circuitry, and when the telephone is in an on/hook condition an output of a second value is produced by the status circuitry. The microprocessor examines the outputs to detect the occurrence of transitions in the outputs between the first and second values representing transitions between on/hook and off/hook conditions of the telephone. For each detected transition, an activity timer within the microprocessor is set to a count corresponding to a predetermined activity-monitoring time period and decremented at a predetermined rate. In the event the activity timer times out, an alarm condition is produced. Thus, so long as the telephone is used during the activity-monitoring time period an alarm condition will be prevented.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application discloses subject matter which is disclosed, andclaimed, in the following co-pending applications:

Ser. No. 965,808, filed Dec. 4, 1978, now U.S. Pat. No. 4,224,478, inthe names of Robert J. Fahey and Martin L. Resnick, entitled "DATATRANSMISSION CIRCUIT", and assigned to GTE Sylvania Incorporated and GTELaboratories Incorporated;

Ser. No. 965,809, filed Dec. 4, 1978, now U.S. Pat. No. 4,220,825, inthe name of Robert J. Fahey, entitled "TELEPHONE STATUS MONITORCIRCUIT", and assigned to GTE Sylvania Incorporated;

Ser. No. 965,756, filed Dec. 4, 1978, now U.S. Pat. No. 4,224,602, inthe names of Richard W. Anderson and Alfred I. Bottner, entitled"SIGNALLING DEVICE", and assigned to GTE Sylvania Incorporated;

Ser. No. 965,757, filed Dec. 4, 1978, in the name of Alfred I. Bottner,entitled "Design for SIGNALLING DEVICE", and assigned to GTE SylvaniaIncorporated;

Ser. No. 973,201, filed Dec. 26, 1978, now U.S. Pat. No. 4,220,872 inthe name of Robert J. Fahey, entitled "D.C. POWER SUPPLY CIRCUIT", andassigned to GTE Sylvania Incorporated;

Ser. No. 973,218, filed Dec. 26, 1978, now U.S. Pat. No. 4,225,792 inthe name of Robert J. Fahey, entitled "DETECTOR CIRCUIT", and assignedto GTE Sylvania Incorporated;

Ser. No. 25,298, filed Mar. 30, 1979, in the names of Richard W.Anderson and Alfred I. Bottner, entitled "Design for HOUSING FORELECTRONIC CIRCUITRY", and assigned to GTE Sylvania Incorporated;

Ser. No. 75,782, filed Sept. 17, 1979, in the name of Richard L. Naugle,entitled "SENSING APPARATUS", and assigned to GTE LaboratoriesIncorporated;

Ser. No. 75,769, filed Sept. 17, 1979, in the names of Richard L. Naugleand William L. Geller, entitled "EXIT-ENTRY APPARATUS", and assigned toGTE Laboratories Incorporated;

Ser. No. 094,015, filed concurrently herewith, in the names of JeffreyR. Fox, Arthur Margolies, Rob Moolenbeek and Martin L. Resnick, entitled"APPARATUS FOR MONITORING AND SIGNALLING SYSTEM", and assigned to GTELaboratories Incorporated;

Ser. No. 094,018, filed concurrently herewith, in the names of RichardW. Anderson, J. Edward Schlener and Martin L. Resnick, entitled"APPARATUS FOR MONITORING AND SIGNALLING SYSTEM", and assigned to GTESylvania Incorporated and GTE Laboratories Incorporated;

Ser. No. 094,013, filed concurrently herewith, in the names of RichardW. Anderson and J. Edward Schlener, entitled "APPARATUS FOR MONITORINGAND SIGNALLING SYSTEM", and assigned to GTE Sylvania Incorporated;

Ser. No. 094,012, filed concurrently herewith, in the names or Robert J.Fahey and Martin L. Resnick, entitled "TELEPHONE STATUS MONITORAPPARATUS", and assigned to GTE Sylvania Incorporated and GTELaboratories Incorporated;

Ser. No. 094,242, filed concurrently herewith, in the names of Robert J.Fahey and Martin L. Resnick, entitled "APPARATUS FOR MONITORING ANDSIGNALLING SYSTEM", and assigned to GTE Sylvania Incorporated and GTELaboratories Incorporated;

Ser. No. 094,245, filed concurrently herewith, in the names of Robert A.Norbedo and Martin L. Resnick, entitled "APPARATUS FOR SIGNALLINGSYSTEM", and assigned to GTE Laboratories Incorporated;

Ser. No. 094,241, filed concurrently herewith, in the name of Martin L.Resnick, entitled "DATA PROCESSING APPARATUS FOR RECEIVING ANDPROCESSING CODED WORDS", and assigned to GTE Laboratories Incorporated;

Ser. No. 094,016, filed concurrently herewith, in the names of RichardW. Anderson, Robert J. Fahey, William R. McClellan, and J. EdwardSchlener, entitled "MONITORING AND SIGNALLING SYSTEM", and assigned toGTE Sylvania Incorporated;

Ser. No. 094,017, filed concurrently herewith, in the names of Hans G.Blank and Martin L. Resnick, entitled "APPARATUS FOR COMMUNICATING WITHPROCESSING APPARATUS OVER A TELEPHONE NETWORK", and assigned to GTELaboratories Incorporated;

Ser. No. 094,243, filed concurrently herewith, in the names of Robert J.Fahey and Robert A. Norbedo, entitled "APPARATUS FOR SIGNALLING SYSTEM",and assigned to GTE Sylvania Incorporated and GTE LaboratoriesIncorporated;

Ser. No. 094,019, now U.S. Pat. No. 4,259,548, filed concurrentlyherewith, in the names of Robert J. Fahey, Robert A. Norbedo and J.Edward Schlener, entitled "APPARATUS FOR MONITORING AND SIGNALLINGSYSTEM", and assigned to GTE Sylvania Incorporated and GTE LaboratoriesIncorporated;

Ser. No. 094,244, filed concurrently herewith, in the names of Robert J.Fahey and Robert A. Norbedo, entitled "APPARATUS FOR SIGNALLING SYSTEM",and assigned to GTE Sylvania Incorporated and GTE LaboratoriesIncorporated; and

Ser. No. 094,246, filed concurrently herewith, in the names of Robert J.Fahey, Robert A. Norbedo and Martin L. Resnick, entitled "VARIABLETIMING SYSTEM", and assigned to GTE Sylvania Incorporated and GTELaboratories Incorporated.

The following co-pending applications are directed to apparatus whichmay be employed in the signalling and monitoring system of the presentinvention:

Ser. No. 75,783, filed Sept. 17, 1979, in the names of Jeffrey R. Fox,Arthur Margolies, and Rob Moolenbeek, entitled "ELECTRICAL POWER SUPPLYAPPARATUS", and assigned to GTE Laboratories Incorporated; and

Ser. No. 084,976, filed Oct. 15, 1979, in the name of William L. Geller,entitled "DIGITAL COMMUNICATIONS RECEIVER", and assigned to GTELaboratories Incorporated.

BACKGROUND OF THE INVENTION

The present invention relates to a monitoring and signalling system.More particularly, the present invention relates to a monitoring andsignalling system such as a home health care system for monitoring theactivities of individuals within their own homes, apartments, etc., andfor providing bi-directional communication between these locations and acentralized communications center.

In recent years, as the general population has become older and thenumber of elderly persons in the population has increased, and also as aresult of increased social welfare legislation directed to the needs ofthese persons, there has been an increased reliance and utilization ofprofessional care institutions such as hospitals, nursing homes andretirement centers for providing health care and maintenance for theseindividuals. A large majority of these individuals are maintained andcared for in such institutions for good and proper reasons, mosttypically for the treatment of medical problems requiring medicalfacilities and equipment and the professional services of doctors,nurses and the like. However, there are a number of individuals who arepresently maintained in institutions without medical reason. Theseindividuals generally have no family or friends to care for them or whodo not wish to impose upon or burden such family or friends and areprepared to sacrifice some measure of independence for the security andfreedom from worry, anxiety, and loneliness that institutions canprovide. It has therefore been recognized that if alternatives toinstitutionalization can be provided, especially for those individualswho do not require constant or continuing institutional attention orobservation, while providing a substantial degree of security andindependence for these individuals, preferably within their own homes,the burdens on the institutional care system can be reduced and resultin lower health care costs. Any such alternatives which would alsoproduce the same results for individuals other than the elderly, such asyoung handicapped, disabled or infirm adults, would also have the effectof improving the quality of life of such individuals and, at the sametime, reducing health care costs.

A variety of apparatus and systems have been proposed heretoforedirected to solutions to the problems as discussed hereinabove. One suchsystem, developed in Sweden, is described in U.S. Pat. No. 3,885,235 andis adapted to monitor passively normal, routine activities of anindividual in his or her own residence and to produce alarm conditionsin the event these routine activities are not performed during somespecified period of time, for example, a period of up to 24 hours. Thesystem as described in the patent includes a plurality of actuatingunits which may be variously located in predetermined areas of theresidence, such as halls, lavatories, bathrooms and bedrooms, and whichmay be associated with apparatus likely to be actuated or used routinelyby the individual during the normal course of the day. This apparatusmay include, by way of example, lighting circuits, radio sets,television sets and household appliances. Actuation or use of any one ofthe actuating units during the aforesaid specific time period will causean electromechanical timer set to this time period to be reset and torepeat its timing cycle. In the event no actuating unit is actuated orused during the time period, for example, due to inactivity orincapacity of the individual, the timer times out after the time periodand an alarm condition, for example, in the form of an audible or visualalarm, is produced by the system indicative of this situation. If thealarm condition was produced as the result of inactivity rather thanincapacity, the user may disable the system by the use of a masterswitch. The master switch may also be used to disable the system whenthe individual leaves his or her residence for a prolonged period oftime, for example, for a period of time greater than the time period ofthe timer. Upon return of the individual, the system is arranged so thatroutine operation of any one of the actuating units will have the effectof resetting the timer and causing the timer to repeat its timing cycle.The system as described above may also include an alarm switch in theresidence for use by the individual in producing alarm conditions duringemergencies, such as medical emergencies or accidents.

In a later version of the system as described in the aforementioned U.S.Pat. No. 3,885,235, known as the "Automatic Warning Aid (AWA)",additional features are provided, including a direction sensitivephotocell optics arrangement in the bathroom; an electronic timer havingtwo time periods, specifically, a short time period associated with thebathroom optics arrangement and a longer time period associated with allother actuating units; a pre-alarm cycle effective prior to an actualalarm cycle and during which an alarm condition can be cancelled oraborted; and remote alarm transmission. In this later system,recognition is given to the fact that the majority of accidents occur inthe bathroom. Accordingly, the system is arranged so that when anindividual enters the bathroom the direction sensitive photocellarrangement detects this entry and causes the timing cycle of theelectronic timer to be reduced to its short time period, for example,about one hour. If the individual does not exit within the one hourperiod, for example, due to incapacity or inactivity of the individual,a pre-alarm cycle will be initiated and, if the pre-alarm cycle is notterminated or aborted by the individual, an actual alarm cycle will beinitiated after passage of a short period of time (e.g., about 1/2hour). In the event the individual exits from the bathroom within theone hour period, the direction sensitive photocell arrangement willdetect this exit and cause the timing cycle of the electronic timer tobe set or returned to its longer time cycle, for example, about 8 hours.During any pre-alarm cycle caused by non-use of any of the actuatingunits within the individual's residence the individual may, unlessincapacitated, abort or cancel the pre-alarm cycle by actuation or useof any actuating unit (which resets the timer) so that no actual alarmcondition will be produced. The alarm condition may be generated locallyor, if desired, transmitted over a telephone network, for example, inthe form of a recorded message, to a central alarm center from whichcommunication with the individual may be attempted and/or help sent orsummoned.

Another system which has been proposed heretofore for passivelymonitoring the activities of individuals within their own residences andfor producing appropriate alarm conditions is described in U.S. Pat. No.3,989,900. In this system, the use of a standard telephone is monitored.Each time the handset of the telephone is lifted off or removed from thecradle of the telephone, for example, during the making and receiving ofroutine telephone calls, a timer set to cycle through a predeterminedtime period, for example, up to 24 hours, is caused to be reset and torepeat its timing cycle. So long as the telephone is used during thetime period of the timer no alarm condition will be produced. If no useof the telephone is made during the time period of the timer, forexample, due to incapacity or inactivity of the individual, a localalarm condition is produced and, simultaneously therewith, a magnetictape player is actuated to dial continuously a plurality of telephonenumbers of locations at which help may be available and to transmit aprerecorded message that help is needed at the address of theindividual. If the timing out of the timer was due to inactivity ratherthan incapacity, the user may, in response to the local alarm condition,abort the alarm condition and data transmission sequence (within a timeperiod of about 90 seconds) by simply lifting and replacing the handsetback on the cradle of the telephone thereby resetting the timer. Thislatter operation may also be used to reset the timer at such time as theindividual plans to leave his residence for a period of time less thanthe predetermined time period of the timer. An activating switch is alsoprovided in the system for activation of the alarm condition in the caseof emergencies. The abovementioned patent also contemplates the use of ahigh speed digital dialer and transmitter in place of the aforementionedmagnetic tape player. In this case, the timing out of the timer willproduce a local alarm condition and, unless the alarm sequence isaborted (for example, within a 5 minute period), the ditigal dialer andtransmitter will operate to seize a telephone line to establishcommunication with the central station. The dialing of the centralstation continues until a receiving signal has been received from thecentral station whereupon an identification signal can be sent to thecentral station.

In still other systems which have been proposed heretofore for enablingindividuals to be maintained within their own residences while providingappropriate alarm signalling in emergency or accident situations, atransmitter is employed by an individual to communicate under a varietyof conditions with control apparatus located on the premises. Thetransmitter, which may be in the form of a small, portable hand heldunit or a unit carried in a pocket or purse or attached to clothing orworn as a pendant (e.g., see U.S. Pat. Nos. 4,121,160 and 4,134,108),may be used by the indiviual to communicate with the control apparatusin a variety of situations, including emergency or accident situations,to respond to periodic check signals or stimuli from the controlapparatus as an indication that "all is well" (e.g., see U.S. Pat. No.3,662,111), or to respond within predetermined time periods of timerapparatus. The signals from the transmitter are typically coded rfsignals employed to control circuitry within the control apparatus.Activation of a transmitter in an emergency or accident situation, orfailure to activate a transmitter at required times, for example, due toincapacity or inactivity, will ordinarily cause an alarm cycle to beinitiated which, if not aborted or cancelled by the individual, willcause an alarm sequence to be initiated for informing others of theemergency, accident or inactivity situation. The alarm sequence may bevariously initiated by digital or tape dialers and include one or moremessages, identification data, etc., to be communicated, for example,over a telephone network, to such organizations or individuals as anemergency center, the police or fire department, ambulance service,doctors, paramedics, rescue teams, relatives, friends or neighbors. Inmany systems, repeated attempts will be made to communicate alarminformation to a central location using one or more telephone numbers,and some systems may include handshaking operations between a localcontrol unit and central equipment and include test calls fordetermining proper functioning of the systems.

While the various systems as described above are useful to a degree inalleviating the problems of individuals living alone, they all haveserious shortcomings and disadvantages which limit their effectivenessand usefulness. As a group, for example, these systems utilize simpledata handling, processing and communication techniques, being limitedmore or less to tape and digital dialing, the transmission and receptionof limited amounts of data, and, in some cases, simple handshaking andparity-checking operations. It is not known, for example, that any ofthese systems employ computers, microprocessors, or the like capable ofperforming significant and substantial data processing, either withinthe residences of individuals or at central locations. As a result,these systems are susceptible to a high false alarm rate and reliabilityproblems, these latter problems being especially exascerbated in thosesystems employing mechanical tape dialers and electromechanical timersand the like. In these systems, therefore, due to the lack ofsophisticated data processing and communications, there is inadequateguarantee, if any, that a successful and satisfactory transmission ofdata, such as alarm conditions or information, has been achieved so thatthose persons charged with acting on this information can adequatelydischarge their duties. The systems as described above, perhaps also asa result of their limited data processing and communicationscapabilities, have limited capability in detecting or pinpointing, anddistinguishing between, the malfunction of various critical componentsthereof, for example, actuating units, control apparatus or telephonelines. In these systems, the malfunction of a critical component thereofwill, assuming that such malfunction is somehow communicated to aresponsible person (e.g., as a result of an alarm condition), ordinarilyrequire service personnel to enter a person's home and check out theentire system or a major part thereof to pinpoint the particular sourceof trouble or malfunction. Further, in those systems employing timershaving one or more resettable time periods (e.g., a one-hour bathroomcycle and/or a regular 8-hour cycle), these time periods are alterableonly within the residences of individuals, thereby requiring costlyservice calls by service personnel to effect the alterations. Thealteration of timer periods only within the residences of individualscan also have the effect of increasing the chances of tampering by theseindividuals.

In addition to the abovementioned general shortcomings anddisadvantages, the systems as described hereinabove have other and morespecific shortcomings and disadvantages which limit their effectivenessand usefulness in a home health care environment. For example, in theSwedish systems the multiple actuating units and the alarm switches arehard-wired to the control units. This hard-wiring operation makes theinstallations of these systems complex, time-consuming and expensive. Inaddition, while using several diverse "passive" actuating units, theSwedish systems do not make use of a common passive actuating unitgenerally available and used frequently in most residences, namely, thetelephone. While the systems described in U.S. Pat. No 3,989,900 employa telephone as a passive actuating unit, no other passive actuatingunits are employed, thereby reducing the scope of monitoring of theactivities of individuals. In addition, only on/hook to off/hooktransitions of the telephone are used to reset the timer in the controlunit. Thus, at the conclusion of a telephone conversation the off/hookto on/hook transition resulting from the individual replacing thehandset on the cradle of the telephone will not reset the timer, therebyhaving the probable effect of increasing the alarm rate of the system.In the case of the systems employing rf transmitters for transmittingalarm conditions or responding to predetermined check signals, thesesystems similarly do not employ passive actuating units and thereby havea reduced scope of monitoring of the activities of individuals and,therefore, a reduced effectiveness.

BRIEF SUMMARY OF THE INVENTION

In accordance with the present invention, apparatus is provided formonitoring usage of a telephone such as may be employed in a system suchas a home health care system as described hereinabove. The telephone asemployed in connection with the apparatus of the present invention isconnected across tip and ring terminals of a telephone system. The tipand ring terminals have a voltage thereacross of a value correspondingto the on/hook condition or the off/hook condition of the telephone.

The apparatus in accordance with the invention includes a status monitorcircuit means for examining tip and ring voltages. The status monitorcircuit means operates to examine on a frequent basis the voltage acrossthe tip and ring terminals and to produce an output having a first valuewhen the voltage across the tip and ring terminals has a valuecorresponding to an on/hook condition and to produce an output having asecond value when the voltage across the tip and ring terminals has avalue corresponding to an off/hook condition. The apparatus inaccordance with the invention further includes an activity timer meansarranged to be set to a count of a predetermined first value. A countaltering means operates to alter each count of the first value to whichthe activity timer means has been set so as to have a predeterminedsecond value at the expiration of a predetermined period of time. Analarm means operates when the count in the activity timer means has beenaltered to its second value to produce an alarm condition.

A first means is arranged to receive the outputs produced by the statusmonitor circuit means and to examine the values of the outputs to detectthe occurrence of transitions in the outputs between the first andsecond values representing transitions between on/hook and off/hookconditions of the telephone. The first means operates in response todetecting the occurrence of transitions in the outputs from the firstvalue to the second value representing a transition of the telephonefrom its on/hook condition to its off/hook condition to produce a firstoutput, and in response to detecting the occurrence of transitions inthe outputs from the second value to the first value representing atransition of the telephone from its off/hook condition to its on/hookcondition to produce a second output.

A second means is arranged to receive the first and second outputsproduced by the first means. The second means operates in response toeach such output to cause the activity timer means to be set to thecount of the first value. As a result, if an output is produced by thefirst means during the predetermined period of time associated with theactivity timer means the existing count of the activity timer means isreplaced by the new count of the first value and the count alteringmeans thereupon operates to alter the new count instead of the previouscount.

BRIEF DESCRIPTION OF THE DRAWING

Various objects, features and advantages of a monitoring and signallingsystem in accordance with the present invention will be had from adetailed discussion taken in conjunction with the accompanying drawingin which:

FIG. 1 is a schematic block diagram of a monitoring and signallingsystem in accordance with the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is described in detail in a co-pending patentapplication Ser. No. 094,019, filed Nov. 14, 1979 in the names of RobertJ. Fahey, J. Edward Schlener, and Robert A. Norbedo, now U.S. Pat. No.4,259,548. The following portions of that co-pending application areincorporated herein by reference:

(a) FIGS. 2-66 and the corresponding brief description thereof under theheading "BRIEF DESCRIPTION OF THE DRAWING"; and

(b) The entire portion of the specification following the heading"DETAILED DESCRIPTION OF THE INVENTION".

What is claimed is:
 1. Apparatus for monitoring usage of a telephone,said telephone being connected across tip and ring terminals of atelephone system, said tip and ring terminals having a voltagethereacross of a value corresponding to the on/hook condition oroff/hook condition of the telephone, said apparatus comprising:statusmonitor circuit means operative to examine on a frequent basis thevoltage across the tip and ring terminals and to produce an outputhaving a first value when the voltage across the tip and ring terminalshas a value corresponding to an on/hook condition and to produce anoutput having a second value when the voltage across the tip and ringterminals has a value corresponding to an off/hook condition; activitytimer means arranged to be set to a count of a predetermined firstvalue; count altering means operative to alter each count of the firstvalue to which the activity timer means has been set so as to have apredetermined second value at the expiration of a predetermined periodof time; alarm means operative when the count in the activity timermeans has been altered to its second value to produce an alarmcondition; first means arranged to receive the outputs produced by thestatus monitor circuit means and to examine the values of said outputsto detect the occurrence of transitions in said outputs between thefirst and second values representing transitions between on/hook andoff/hook conditions of the telephone, said first means being operativein response to detecting the occurrence of transitions in said outputsfrom the first value to the second value representing a transition ofthe telephone from its on/hook condition to its off/hook condition toproduce a first output, and operative in response to detecting theoccurrence of transitions in said outputs from the second value to thefirst value representing a transition of the telephone from its off/hookcondition to its on/hook condition to produce a second output; andsecond means arranged to receive the first and second outputs producedby the first means and operative in response to each such output tocause the activity timer means to be set to the count of the firstvalue, whereby if an output is produced by the first means during thepredetermined period of time associated with the activity timer meansthe existing count of the activity timer means is replaced by the newcount of the first value and the count altering means thereupon operatesto alter the new count instead of the previous count.
 2. Apparatus inaccordance with claim 2 wherein the first means comprises:storage meansoperative to store successive outputs produced by the status monitorcircuit means; and means arranged to compare the values of successiveoutputs stored in the storage means and operative when successive onesof the outputs have first and second values representing a transition ofthe telephone from its on/hook condition to its off/hook condition toproduce a first output and operative when successive ones of the outputshave second and first values representing a transition of the telephonefrom its off/hook condition to its on/hook condition to produce a secondoutput.
 3. Apparatus in accordance with claim 2 wherein:the first valueof each count set into the activity timer means represents thepredetermined period of time; and the count altering means includesdecrementing means operative to decrement the count set into theactivity timer means from the first value to the second value. 4.Apparatus in accordance with claim 3 wherein the second meanscomprises:count storage means arranged to store a count of the firstvalue; and means operative in response to each output produced by thefirst means to cause the count of the first value stored in the countstorage means to be loaded into the activity timer means thereby to beset to the count of the first value.
 5. Apparatus for monitoring usageof a telephone, said telephone being connected across tip and ringterminals across which a ringing voltage may be present and besuperimposed on normal voltages corresponding to on/hook and off/hookconditions of the telephone, said ringing voltage having a predetermined"on" time and a predetermined "off" time, said apparatuscomprising:control means adapted to receive a series of pairs of spacedpulses, the first pulse of each pair of pulses being spaced from thefirst pulse of the next pair of pulses by a first duration and thepulses of each pair of pulses being spaced from each other by a secondduration, said second duration having a value intermediate to the valuesof the "on" and "off" times of the ringing voltage, said control meansbeing operative in response to each pulse received thereby to beactuated between first and second operating states; charging circuitmeans arranged when the control means is in its first operating state tobe placed by the control means in circuit with the tip and ringterminals and when the control means is in its second operating state tobe removed by the control means out of circuit with the tip and ringterminals; said charging circuit means being operative when coupled incircuit with the tip and ring terminals by the control means to becharged to the value of the voltage then present across the tip and ringterminals; status circuit means arranged when the control means is inits second operating state to be connected by the control means incircuit with the charging circuit means, said status circuit means beingoperative when connected with the charging circuit means to examine thevoltage to which the charging circuit means has been charged and whenthe value of the voltage bears a predetermined first relationship to aprescribed reference value to produce an output of a first valuerepresentative of an apparent on/hook condition, and operative when thevalue of the voltage bears a predetermined second relationship to theprescribed reference value to produce an output of a second valuerepresentative of an apparent off/hook condition; first means arrangedto receive the outputs produced by the status circuit meanscorresponding to each pair of pulses and to compare the values of saidoutputs, said processing means being operative if the outputscorresponding to a pair of pulses both have the first value to producean on/hook output representative of an on/hook condition and operativeif the outputs corresponding to a pair of pulses both have the secondvalue to produce an off/hook output condition representative of anoff/hook condition; activity timer means arranged to be set to a countof a predetermined first value; count altering means operative to altereach count of the first value to which the activity timer means has beenset so as to have a predetermined second value at the expiration of apredetermined period of time; alarm means operative when the count inthe activity timer means has been altered to its second value to producean alarm condition; second means arranged to receive the outputsproduced by the first means and to examine the values of said outputs todetect the occurrence of transitions in said outputs between the firstand second values representing transitions between on/hook and off/hookconditions of the telephone, said second means being operative inresponse to detecting the occurrence of transitions in said outputs fromthe first value to the second value representing a transition of thetelephone from its on/hook condition to its off/hook condition toproduce a first output, and operative in response to detecting theoccurrence of transitions in said outputs from the second value to thefirst value representing a transition of the telephone from its off/hookcondition to its on/hook condition to produce a second output; and thirdmeans arranged to receive the first and second outputs produced by thesecond means and operative in response to each such output to cause theactivity timer means to be set to the count of the first value, wherebyif an output is produced by the second means during the predeterminedperiod of time associated with the activity timer means the existingcount of the activity timer means is replaced by the new count of thefirst value and the count altering means thereupon operates to alter thenew count instead of the previous count.
 6. Apparatus in accordance withclaim 5 wherein the second means comprises:storage means operative tostore successive outputs produced by the first means; and means arrangedto compare the values of successive outputs stored in the storage meansand operative when successive ones of the outputs have first and secondvalues representing a transition of the telephone from its on/hookcondition to its off/hook condition to produce a first output andoperative when successive ones of the outputs have second and firstvalues representing a transition of the telephone from its off/hookcondition to its on/hook condition to produce a second output. 7.Apparatus in accordance with claim 6 wherein the first meanscomprises:status storage means operative to store therein the values ofsuccessive outputs produced by the status circuit means corresponding toeach pair of pulses; means operative to compare the values of successiveoutputs stored in the status storage means; and means operative if thevalues of successive outputs are the same to produce an output conditionindicating that the values are the same and to employ said outputcondition with the particular first or second value of the output toprovide an on/hook output or off/hook output representative of theon/hook condition or the off/hook condition, respectively.
 8. Apparatusin accordance with claim 7 wherein:the ringing voltage has an "on" timeof two seconds and an "off" time of four seconds; and the control meansis adapted to receive the series of pairs of spaced pulses wherein thefirst pulse of each pair of pulses is spaced from the first pulse of thenext pair by one minute and the pulses of each pair of pulses are spacedfrom each other by three seconds.
 9. Apparatus in accordance with claim8 wherein:the first value of each count set into the activity timermeans represents the predetermined period of time; and the countaltering means includes decrementing means operative to decrement thecount set into the activity timer means from the first value to thesecond value.
 10. Apparatus in accordance with claim 9 wherein the thirdmeans comprises:count storage means arranged to store a count of thefirst value; and means operative in response to each output produced bythe first means to cause the count of the first value stored in thecount storage means to be loaded into the activity timer means therebyto be set to the count of the first value.